In a multi-shed warp-wave loom, multiple shed retainers are employed which sustain multiple sheds traveling in a wave-like form in a direction parallel with the warp threads toward the fell of the cloth. Each of these sheds receives a weft thread, which is usually inserted by a fluid jet (i.e., air). A separate shed forming apparatus is usually provided for forming the warp sheds by elevating and lowering alternate warp threads in a conventional manner.
Multi-shed weaving systems have been developed which utilize a fluid jet of fluid, usually air to insert the weft thread through the open sheds. In such devices the fluid, along with the weft thread, are directed through a weft guide channel and shed retainer positioned within the open warp shed. The weft guiding channel is necessary to direct the jet of air or liquid within the open shed, and to maintain the speed of the jet at the velocity required for transporting the weft thread completely through the open shed while preventing the jet from interfering with the warp threads forming the open shed. Reference is made to U.S. Pat. No. 4,425,946 for a complete and detailed description of such multished weaving systems utilizing a fluid jet for weft insertion.
In a shed retainer for a multi-shed loom utilizing a fluid jet, such as an air jet, for weft insertion, a problem arises in terms of efficiency of weft insertion due to the nature of the construction requirements for the shed retainers. For example, as disclosed in U.S. Pat. No. 4,425,946, weft guide shed retainers can be formed as individual, slotted tubular sections that must be inserted between the warp threads into each shed, moved toward the fell of the fabric to hold the shed open, and then removed from the shed between the warp threads while disengaging the inserted weft thread. The multi-segmented construction of the weft guide shed retainers inherently requires discontinuites between the various segments which results in leakage of air and loss of fluid momentum traveling through the shed retainer. Inherently, the efficiency of weft insertion is affected by the mass and velocity of the fluid traveling through the shed retainer through which the weft is inserted.